Selaginella microdonta A.C. Sm.

Valdespino, Ivan A., 2015, Novelties in Selaginella (Selaginellaceae - Lycopodiophyta), with emphasis on Brazilian species, PhytoKeys 57, pp. 93-133 : 110

Selaginella microdonta A.C. Sm.

Selaginella microdonta A.C. Sm., Bull. Torrey Bot. Club 58: 313. 1931. - Type. Venezuela. Amazonas: on slope of Ridge 24 and summit of Mount Duida, 1800 m, Aug 1928-Apr 1929, G.H.H. Tate 509 (holotype: NY! [NY00144140]; isotypes: BM [BM000936552]-image!, US-fragment! [US00135732]).

Additional specimen examined.

BRAZIL. Amazonas: Alto Río Negro, Cucui, Serra Tunui, 29 Apr 1975, Cavalcante 3056 (MG).

Discussion.

Selaginella microdonta was previously known only from Venezuela ( Alston et al. 1981, Smith 1995, Cremers et al. 2007, Mostacero 2008); its range is now extended to include Brazil. This species is characterized by being a minute, creeping plant with coriaceous leaves, the median leaves ovate, ovate-deltate with oblique to rounded bases with the outer ones prominent. Furthermore, these leaves have prominent, often arcuate midribs (making the halves of the laminae unequal), serrate to serrulate margins, and acute apices; the lateral leaves are broadly ovate-elliptic with thickened margins, these denticulate to entire, and acute apices tipped by 1-3 teeth. In Brazil, Selaginella microdonta may be confused with Selaginella wurdackii , from which it differs by its creeping habit and smaller median leaves with acute apices. According to Valdespino (1992), Selaginella microdonta is morphologically related to Selaginella cardiophylla Valdespino and Selaginella hemicardia Valdespino. The possible interrelationships and distinguishing characters are further discussed in Valdespino (1992).